Hull Maury L, Simileysky Alexander, Howell Stephen M
Department of Biomedical Engineering, Department of Mechanical Engineering, Department of Orthopaedic Surgery, University of California Davis, Davis, CA 95616, USA.
Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA.
Bioengineering (Basel). 2024 Jan 8;11(1):62. doi: 10.3390/bioengineering11010062.
Because kinematic alignment (KA) aligns femoral components in greater valgus and with less external rotation than mechanical alignment (MA), the trochlear groove of an MA design used in KA is medialized, which can lead to complications. Hence, a KA design has emerged. In this study, our primary objective was to quantify differences in trochlear morphology between the KA design and the MA design from which the KA design evolved. The KA and MA designs were aligned in KA on ten 3D femur-cartilage models. Dependent variables describing the morphology of the trochlea along the anterior flange, which extends proximal to the native trochlea, and along the arc length of the native trochlea, were determined, as was flange coverage. Along the anterior flange, the KA groove was significantly lateral proximally by 10 mm and was significantly wider proximally by 5 mm compared to the MA design ( < 0.0001). Along the arc length of the native trochlea, the KA groove was significantly lateral to the MA design by 4.3 mm proximally ( ≤ 0.0001) and was significantly wider proximally by 19 mm than the MA design. The KA design reduced lateral under-coverage of the flange from 4 mm to 2 mm ( < 0.0001). The KA design potentially mitigates risk of patellofemoral complications by lateralizing and widening the groove to avoid medializing the patella for wide variations in the lateral distal femoral angle, and by widening the flange laterally to reduce under-coverage. This information enables clinicians to make informed decisions regarding use of the KA design.
由于运动学对线（KA）使股骨组件的外翻角度更大且外旋角度更小，相比于机械对线（MA），用于KA的MA设计的滑车沟会向内侧移位，这可能导致并发症。因此，一种KA设计应运而生。在本研究中，我们的主要目标是量化KA设计与其演变而来的MA设计之间滑车形态的差异。在十个三维股骨 - 软骨模型上按照KA方式对KA和MA设计进行对线。确定了描述滑车沿向前延伸至天然滑车近端的前凸缘以及天然滑车弧长的形态的因变量，以及凸缘覆盖情况。沿前凸缘，与MA设计相比，KA滑车沟近端显著向外侧移位10毫米，近端宽度显著增加5毫米（<0.0001）。沿天然滑车的弧长，KA滑车沟近端比MA设计显著向外侧移位4.3毫米（≤0.0001），近端宽度比MA设计显著增加19毫米。KA设计将凸缘外侧覆盖不足从4毫米减少至2毫米（<0.0001）。KA设计可能通过使滑车沟向外侧移位并加宽以避免在股骨远端外侧角度有较大变化时使髌骨向内侧移位，以及通过向外侧加宽凸缘以减少覆盖不足，从而降低髌股并发症的风险。这些信息使临床医生能够就KA设计的使用做出明智的决策。
